Commercially available herbicide and pesticide formulations are generally in the form of wettable powders, dusts or granules. However, such formulations are not always desirable as they present problems in handling of the formulations and are particularly irritating to the grower-user. Moreover, many herbicide and pesticide active ingredients are difficult to suspend and thus do not lead to easily produced formulations of the type mentioned. In addition, in the past certain active ingredients that are insoluble organic acids were formed as dialkylamine salts in order to obtain the necessary suspension of the product. However, such dialkylamine salts have the potential of forming highly undesirable nitroso amine derivatives in the environment.
It is, therefore, highly desirable to obtain herbicide and pesticide formulations which avoid one or more of these disadvantages of prior art formulations. Moreover, it would also be advantageous to provide such new and improved herbicide and pesticide formulations which, in addition to avoiding one or more of the prior art problems, also leads to formulations that may possess one or more additional advantages over the prior art formulations.
It has been proposed in the earlier application to obtain such flowable formulations by the use of aluminum hydroxide gel as the suspending agent. However, the use of aluminum hydroxide for the preparation of formulations containing active ingredients such as 2,4-D, dicamba and the like in their free acid form is not entirely suitable and in some cases undesirable because of the chemical reaction that occurs between the acid function of the active ingredient and the aluminum hydroxide. This reaction can cause the initially flowable suspension to set up into a relatively hard mass that is difficult to resuspend and is not an acceptable formulation. In addition, such reaction causes a substantial portion of the active ingredient to be converted to its aluminum salt.